Can't access nextcloud after setting up redis

Not sure why it doesn’t work for you, but here’s a few things you could check…

  • Check if the Redis server installed and the Redis service is running:

    systemctl status redis.service
    
  • Check if the appropriate PHP module is installed and enabled?

    apt list php*-redis
    
    php --ri redis
    
  • Check the config file /etc/redis/redis.conf, especially the following lines:

    bind 127.0.0.1 ::1
    port 0
    unixsocketperm 770
    unixsocket /var/run/redis/redis-server.sock
    

    If unsure post your config here, you can use the follwing command to print only the uncommented lines:

    cat /etc/redis/redis.conf | grep -v '^$\|^#'
    
  • Check if the www-data user is in the redis group

    groups www-data